The greatest change in thermal stress
Frequently Asked Questions

This ranking shows the countries that are going to suffer the greatest change in thermal sensation. The thermal sensation is measured with the Universal Thermal Climate Index, UTCI, which takes into account not just temperature but also humidity, wind and radiation, all factors significantly affecting the human body Bröde et al. 2012, Di Napoli et al. 2020).

To calculate each ranking, Lobelia Earth has created the UTCI data projections dataset. In order to compute future UTCI fields, we use climate projections of the different variables involved in the computation of the UTCI. Currently, we have used CMIP5 climate projections from the ACCESS1-0 model under the socioeconomic business as usual scenario (RCP8.5) ranging from the year 2005 to 2100. The different rankings are computed by looking at different months of the year and different times of the day when UTCI values may reach maximum or minimum values. ​

Climate models are very complex and highly idealized representations of the main elements that interact within the climate system (i.e. atmosphere dynamics, ocean currents, biosphere, solar radiation…) and are used to understand how the climate will evolve in time.

In these rankings we do look at the average of the daily maximum values of UTCI during the warmest month of the year, which is July in the northern hemisphere and January in the southern hemisphere.

Analogously, for cold stress, we look at the average of the daily minimum values of UTCI during the coldest month of the year, which is January in the northern hemisphere and July in the southern hemisphere.

To generate the rankings, we combine the projected fields of UTCI with the countries’s population data from the Gridded Population of the World GPWv4 provided by the SEDAC. Specifically we use the Population Count version adjusted by the United Nations. For each country's geospatial domain, we sum all the population counts that lie within the area with UTCI values above the specified heat stress threshold or below the specified cold stress threshold. Despite upper and lower boundaries cannot be defined as they differ from country to country and from person to person, in general the thresholds of 38°C and -13°C for heat and cold stress respectively, are identified as extreme values beyond which the human body starts to experience important physiological disorders Blazejczyk et al. 2010.

Yes. The UTCI dataset we created is global. A ranking could be extracted using the variables we decide: countries in a continent, cities in a country, or in a specific region.

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